What about Add "Day of the Week" to LCD Items "Sensor item" or "Simple sensor Item"?
Without change "Short date" settings in Windows Control Panel?
Example: https://www.howtogeek.com/194103/how-to-put-the-day-of-the-week-into-the-windows-taskbar-clock/
explanation of formatting rules, see http://msdn.microsoft.com/en-us/library/dd317787(v=VS.85).aspx
for full syntax. (Or Google for GetDateFormat)
Example:
date_format dd.MM.yyyy dddd
If possible...